In the manufacture of aluminum engine cylinder blocks, it is customary practice to install steel liner sleeves in the cylinder bores of the engine block by inserting the liner sleeves into the bores with a snug fit therein, while the bore walls are in a heated condition, to thereby produce a tight shrink fit of the bore walls around the liner sleeves on subsequent cooling and resulting circumferential contraction of the bore walls.
In one such liner sleeve installation procedure commonly employed in the past by some aluminum engine manufacturers, the residual furnace heat retained by the engine block is utilized to establish the heated and expanded diameter condition of the cylinder bores which is essential for the shrink fitting of the cylinder bore walls around the liner sleeves. One of the problems experienced, however, with this particular manufacturing procedure utilizing the residual furnace heat retained by the engine block, is that the liner sleeves tend to be extruded out of the aluminum block bore upon cooling. While this extruding movement is not particularly great, amounting to perhaps several thousandths of an inch, it nevertheless cannot be tolerated in the finished product. It is believed this undesirable extruding movement of the liner sleeve is caused by the aluminum of the engine block cooling and shrinking onto the liner sleeve first at the bottom end of the liner sleeve and before it shrinks onto the top end thereof.
In previously known heat shrinking manufacturing procedures using induction and/or other methods of heating a metal object or body part in a bore of which a cylindrical metal sleeve is to be shrink fitted, the metal object or body part is normally heated in one manufacturing operation conducted at one processing station to the desired predetermined processing temperature and then transferred to the second or sleeve inserting operation at another processing station by a transfer operation which may not be precisely controllable timewise and involves a varying time delay such as requires a more extensive heating of the object or body part in order for it to retain sufficient heat for the necessary expansion of the object to permit the insertion into the bore thereof of the metal sleeve to be shrink fitted therein.